Conventionally, there is known an electrically driven vehicle equipped with a battery usable for running. It is known that such an electrically driven vehicle may be a golf cart, a forklift, a construction machine or the like. A high degree of freedom of movement may be secured by configuring the electric drive vehicle to use a battery to supply power to a source for running.
The use of the battery for power supply need to charge the battery. In this regard, Patent Document 1 discloses a vehicle equipped with an engine generation type charger. This vehicle is configured to always charge the battery by the engine generation type charger when the vehicle is in use. Therefore, the vehicle is capable of preventing the depth of discharge of the battery from becoming large. Patent Document 2 discloses a power supply system for a battery driven type construction machine in which a vehicle for power charge is delivered in accordance with a power supply instruction from the battery driven construction machine. This system is capable of supplying power to the battery without installation of battery charging equipment in the working site.
Besides, arts that would be relative to the present invention are disclosed in Patent Documents 3 through 5. In these documents, there are disclosed arts of operating or stopping an engine under a given condition. Particularly, Patent Document 3 discloses an art of making it possible to easily remove an engine from a vehicle for maintenance and inspection, and an art of stopping an engine and then removing the engine in removal of the engine from the vehicle.